Circuit-breaking apparatus for electrical circuits.



"No. 688,359. Patented Dec. I0, i90l.

L. B. ST|LLWELI..

CIRCUIT BREAKING APPARATUS FOR ELECTRICAL CIRCUITS.

(Application filed Jim 12, 1900.

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IHBGUIT BREAKING APPARATUS FOR ELECTRICAL CIRCUITS.

(Application filed June 12, 1900.)

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(No Model.)

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- ATTORNEY.

NORRIS PHTCRS co, momumo" WASHINGTON u c UNITED STATES PATENT OFFICE.

LEWIS B. STILLWELL, OF NIAGARA FALLS, NEXV YORK, ASSIGNOR TO ESTINGHOUSEELECTRIC AND MANUFACTURING COMPANY, A

CORPORATION OF PENNSYLVANIA.

CIRCUIT-BREAKING APPARATUS FOR ELECTRICAL CiRCUITS.

SPECIFICATION forming part of Letters Patent No. 688,359, dated December10, 1901.

Application filed June 12,1900.

To all whom it may concern.-

Be it known that I, LEWIS B. STILL'WELL, a citizen of the United States,residing at Niagara Falls, in the county of Niagara and State of NewYork, have invented a new and useful Improvement in Circuit-BreakingApparatus for Electrical Circuits, of which the following is aspecification.

My invention relates to systems of electrical distribution, andparticularly to means employed for protecting such systems from injuriesresulting from short circuits and overloads.

The object of my invention is to provide a simple and effective meansfor breaking an electric circuit which is made operative by an excessivecurrent of normal direction in such circuit, but which is not operatedby a reverse current of any volume or duration.

WVith this end in View I have devised the means illustrated in theaccompanying drawings, in which-- Figure 1 is a front elevation of acircuitbreaker and its controlling and actuating mechanism constructedin accordance with my invention, the circuits and certain parts of theapparatus being illustrated diagrammatically. Figs. 2 and 3 are views,similar to Fig. 1, of a portion of the apparatus shown in said figure,but illustrating it under different conditions of service. Fig. 4 is adiagram of a system of electrical distribution in connection with whichmy invention is adapted for use.

In systems of electrical distribution in which energy is supplied totranslating devices by a single generator or by a plurality ofgenerators operating in parallel it is desirable to provide means foropening the circuit either immediately upon the occurrence of anexcessive flow of current or at the end of a predetermined interval oftime during which such excessive flow is maintained, and such means arewell known in the art. The circuit-breaking devices heretofore employednot only serve to interrupt the circuits in connection with which theyare employed when an excessive current of normal direction is producedby a short circuit or an overload,

Serial No. 20,097. (No model.)

but they operate in the same manner it an excessive current flows in areverse direction to the normal. Under certain conditions and in certainrelations circuit-breakers of the character indicated are entirelysatisfactory. There are other conditions, however, under which acircuit-breaker that will discriminate between an excessive current ofnormal direction and one that flows in the reverse direction and whichwill not be operated by the latter is greatly to be desired. Ve mayassume, for example, that a set of alternatingcurrent dynamos areconnected to a set of bus-bars from which a number of rotary convertersare operated in parallel through appropriate feeder-circuits and thatthe rotary converters supply direct current in parallel to a singlepower-circuit. \Vith such an arrangement of apparatus if a short circuitshould be established between the powerhouse circuit breaker or breakersof any feeder-circuit and the rotary converter of that circuit the largeamount of stored-up energy in the other rotary converters of the systemmight cause excessive currents to flow from them to thealternating-current bus-bars before the opening of the circuit-breakersof the short circuited feeders would be effected. Under suchcircumstances it the circuitbreakers should be free to open under theaction of the reverse currents all of the feedercircuits might beinterrupted because of a short circuit in only one of them. I haveaccordingly devised the means which will now be described, referencebeing had first particularly to Figs. 1, 2, and 3 of the drawings.

I have shown my invention as applied to three-phase alternating-currentcircuits; but

it will be understood that the invention is or may be adapted for use inconnection with obviously each of the conductors 1, 2, and 3 might beprovided with protecting devices, if desired. The primaries 4 and 4 ofseries transformers 5 and 5 are respectively included in conductors 1and 3, and the primaries G and (3 of shunt-transformers 7 and 7 havetheir terminals respectively connected to conductors 1 and 2 andconductors 3 and 2, as shown in Fig. 1 of the drawings.

The apparatus connected to the secondary 8 of the transformer 7 and tothe secondary 9 of the transformer 5 will be now described, it beingunderstood that the secondaries 3 and 9 of the transformers 7 and 5 areconnected to apparatus for protecting the side 2 and 3 of the circuit,which is the same in all respects as the apparatus connected to the side1 and 2 of the circuit.

The terminals of the secondary 8 of the transformer 7 are connected tothe terminals of the field-magnet winding 10 of a small motor 11 bymeans of conductors 12 and 13. The pole-pieces 14 of the motor 11partially surround an armature 15, the specific construction of which isnot illustrated; but it may be understood that it is provided with awinding of ordinary construction which is connected to acommutator-cylinder 16, both being mounted upon a shaft 17. Fastenedrigidly to the shaft 17 is one end of a lever 18, the other end of whichis provided with a laterally-projecting tooth 19, the purpose of whichwill hereinafter appear. The motor 11 is provided with two brushes 20and 21, the brush 20 being connected by means of a conductor 22 to oneterminal of the secondary 9 of the transformer 5. The brush 21 isconnected to one terminal of the winding 23 of an electromagnet 24, theother terminal of the winding 23 being connected to a stationarycontact-terminal 25 and also through a conductor 26 to abrush 27. Thisbrush 27 is arranged to'bear upon the periphery of a wheel 28,0fnon-conducting material, mounted upon a shaft 29 and provided forapproximately three-fourths of its circumference with a contact rim orband 30, this band being electrically connected to the shaft 29 by aconductor 31. The wheel 28 is geared to a wheel 32 by means of aclock-train 33, which may be driven bya spring or a weight in the usualmanner. The wheel 32 is provided with a lug or tooth 32, that projectsfrom its periphery in such position as to engage with the end 34 of apivoted arm or locking-pawl 35. YVhen the several members are in thepositions indicated in Fig. 1, the arrangement and connection ofcircuits are such that the armature 15 of the motor 11 will tend toretate in a contra-clockwise direction when the direction of the currentin the main circuit is normal. The movement of the armature aconsiderable distance is, however, prevented by a stop-pin 3b, withwhich the rear side of the arm 18 engages. The armature 37 of the magnet24 is pivoted at 38 to an upright 39, forming part of a suitable bracket40.

The armature 37 projects beyond the pivot 38 and is provided at theouter end of the projection with a hooked portion 41, in which rests apin 42, carried by a vertical rod 43, the upper end of which ispivotally attached to the arm 35. The rod 43 projects through an openingin the extension 44 of the bracket 40, and the projecting end of the rodis surrounded by a coiled spring 45 and provided with an adjusting-nut46, in order that the pulling-down action of the spring may beregulated, if desired. The armature 37 is provided with anupwardly-projeeting circuit making and breaking arm 47, which is movedinto engagement with the contact-terminal 25 and an adjacent similarterminal 25 when the magnet 24 is energized to draw its armature 37 intocontact with its upper end. The contactterminal 25 is connected by meansof a conductor 48 to one terminal of the winding 4!) of an electromagnet50, the other terminal of the winding 49 being connected by means of aconductor 51 to one terminal of the secondary 9 of the transformer 5 andalso to the band or strip 30 on the Wheel 28 through the shaft 29 andthe conductor 31. The circuit-breaker proper, 52, has two stationarycontact-terminals 53, that are respectively connected to adjacentterminals of the main conductor 1, and these terminals 53 are bridged bya curved movable contact mem ber 54, this member being connected to ashaft 55 by means of toggle-levers 56, one of these levers having alocking-piece 57, with which a hook on the end of latch 58 engages whenthe circuit-breaker is closed by means of the handle 59. The weight uponthe hook end of the arm 58 is sufficient to normally hold the armature60, which constitutes an extension of said arm 53, away from its magnet50.

The operation of the apparatus will now be described. Assuming that theseveral parts are in the positions indicated in Fig. 1 and thatconsequently a current of less volume than that for which the apparatusis set to open the circuit-breaker is flowing in a normal direction inthe main circuit, if now the current in this main circuit increasesbeyond the Volume for which the apparatus is set the current will flowfrom the secondary 9 of the transformer 5 through the conductor 22, thecommutator and armature of the motor 11, the winding 23 of theelectromagnet 24, the conductor 26, brush 27, rim 30, shaft 29, andconductor 51 back to the transformer-secondary 9. The magnet 24 beingthus energized will cause its armature 37 to move the member 47 intoengagement with the contact-terminals 25 and 25 and by means of the rod43 to raise the end of the lever 35 out of e11- gagement with theprojection 32 on the wheel 32. This releases the clock-train, which willcontinue to run so long as an excessive current continues to flow up tothe point where the brus 27 passes from the rim 30 onto the insulatedportion of the periphery of the wheel 28, as is indicated in Fig. 2. Ifthe excessive IIO current continues to flow after the circuit isinterrupted at the brush 27, it will be compelled to pass from themagnet-coil 23-through contact-terminal 25, contact-arm 47,contactterminal conductor 48, the winding 49 of magnet 50, and conductor51. The magnet 50 will therefore actuate the armature 60, and thuseifectthe release of the circuit-breaker in order that it may open. Theclock-train will continue to revolve until the projection 32 comes intoengagement with the end of arm 35, when the parts will be set foroperation, the same as is indicated in Fig. 1, except for the fact thatthe circuit-breaker would not, under these circumstances, be closed. Thepositions of the several parts of the apparatus when the circuit-breakeris open are indicated in Fig. 2, except that, as there shown, the magnet24 has not released its armature. Assuming now that the parts are in theposi tions indicated in Fig. 1 and that a flow of current that exceedsthat for which the apparatus is set takes place in the reverse directionto the normal, the armature of the motor 11 will be rotated a sufficientdistance in a clockwise direction to bring the projection 19 on the endof the arm 18 into engagement with the periphery of the wheel 32. Themagnet 2 L will be energized and the parts will be brought into theseveral positions which they would occupy if the excessive current wasin a normal direction, except as regards the armature of the motor 11and the locking-arm projecting therefrom. The clock-train will thereforecontinue to rotate the wheel 28, provided the excessive currentcontinues to flow, until the stop projection 32 comes into engagementwith the projecting end 19 of the arm 18, as indicated in Fig. 3. Therotation of the wheel 28 is thus stopped before the brush 27 passes fromthe conducting-band 30, and since the contact-terminals 25 and 25" arebridged by the member 17 the magnet 50 remains shortcircuited and thecircuit-breaker does not open. When the current again resumes its normaldirection, the motor 11 will move the arm 18 in a contra-clockwisedirection, and thus release the clock-train, which will move the wheels28 and 32 into the position shown in Fig. 1, thus resetting theapparatus for further use.

Referring now to Fig. 1, in connection with the other figures of thedrawings, A. and B are three-phase generators supplying energy tobus-bars a, b, and 0. Leading from these bus bars are a plurality ofthree phase feeder-circuits, three of such circuits being shown in thedrawings. It will be understood, however, that any other desired numberof such circuit-s may be employed, if desired. Inasmuch as these sets ofconductors are or may be alike, I have employed the numerals 1, 2, and 3to designate the several conductors of each set. I haveindicated theconductors 1 and 3 as provided adjacent to the buss-bars withcircuit-interrupting devices O, these devices being showndiagrammatically and in conventional form, but being intended to embodyin practice the essential features of the apparatus already described.The conductors 1, 2, and 3 extend to and provide energy for operating arotary converter D, which supplies directcurrent energy to conductors eandf, which may be a railway or other power circuit. One of thedirect-current conductors d and (1, leading from the rotary converter Dto the conductors e and f, is provided with a circuit-breaking device E.It will be understood that this diagram which we have just beenconsidering shows only the essential elements of a distributing system,the controlling, measuring, and other apparatus being omitted for thesake of simplicity. Circuit-breakers G are of the automatic type that wehave been considering and are intended to open the circuits in whichthey are placed when the currents in such circuits exceedapredeterminedamount and are maintained a certain predetermined length of time,provided such currents are delivered to the rotary converters from thebus-bars. If, however, a short circuits accurs in any one of thefeeder-circuits anywhere between its circuit-breakers C and its rotaryconverter D, the rotary converters of the other feeder-circuits, whichmay be of large size and possess a large amount of storedup energy intheir rotating elements, may act as generators of alternating currentsand deliver such currents for a short time to the busbars at thepower-house. If these currents should exceed in amount that for whichthe circuit breakers have been set, the latter would be actuated to openthe circuits, and thereby cause much inconvenience and a possibleshutdown of the entire system under the usual conditions of operation.With my construction and arrangement of apparatus, however, no backwardHow of energy through any of the feeder-circuits by reason of a shortcircuit in any other feeder-circuit or from any other cause can trip itscircuit breaker or breakers, and thus withdraw it or them from service.

I desire it to be understood that my inven tion is not limited to anyparticular type of circuit-breaker or in other respects to the speciticdetails of apparatus shown and described.

I claim as my invention 1. In a system of electrical distributioncomprising a plurality of feeding or distributing circuits supplied fromone set of busbars, a circuit-breaker for each circuit having meansactuated by excessive current of normal direction to effect its releaseand having means for preventing its release when subjected to reversecurrent.

2. A circuit-breaker for electrical circuits having means for locking itin circuit-closing position, means for opening it when released,releasing means actuated by an excessive current of normal direction andmeans for preventing release when the current is reversed.

3. In a system of electrical distribution comprising a plurality offeeding or distributing circuits supplied from one set of busbars, acircuit-breaker for each circuit having locking and releasing devicesand provided with an actuating means for the releasing device which isrendered active by an excessive current of normal direction, and whichis not affected by a reverse current.

4:. A circuit-breaker provided with means for actuating it at the end ofa predetermined interval of time during which an excessive current ofnormal direction is maintained and with means for looking it againstoperation when a reverse current flows in its circuit.

5. In a system of electrical distribution comprising a plurality offeeding or distributing circuits supplied in parallel from a source ofenergy, a circuit-breaker for each circuit provided with means fornormally holding it in circuit-closing position, in combination with areleasing device, means operated by excessive current of normaldirection for actuating said releasing device and dependent upon themaintenance of such current during a predetermined interval of time andmeans for locking said actuating means when a reverse current flowsthrough the circuit containing the breaker.

6. In a system of electrical distribution comprising a plurality ofcircuits supplied in parallel from a source of energy, a normally closedcircuit-breaker for each circuit provided with releasing means operatedby an excessive current of normal direction, in combination with timemechanism and connections for retarding the action of said releasingmeans a predetermined length of time after the beginning of a maintainedflow of excessive current and a controlling device for said timemechanism which prevents release of the circuit-breaker when a reversecurrent flows in the circuit.

7. In a system of electrical distribution comprising a plurality ofcircuit-s supplied in parallel from a source of energy'and supplying apower-circuit through rotary converters, a normally closedcircuit-breaker for each circuit provided with releasing means operatedby an excessive current of normal direction, in combination with timemechanism and connections for retarding the action of said releasingmeans a predetermined length of time after the beginning of a maintainedflow of excessive current and a controlling device for said timemechanism which prevents release of the circuit-breaker when a reversecurrent flows in the circuit.

8. In a system of electrical distribution, the combination with a sourceof polyphase alternating-current energy and a plurality of circuitsconnected in parallel to said source, of rotary converters severallyreceiving energy from said circuits and supplying directcurrent energyin parallel to a power-circuit, circuit-breakers for said parallelcircuits provided with opening means which is rendered operative by anexcessive current of normal direction and with means for rendering saidopening means inactive when a reverse current flows.

In testimony whereof I have hereunto subscribed my name this 7th day ofJune, 1900.

LEWIS B. STILLVVELL.

IVitnesses:

FRANCIS U. WILcox, E. F. SCHUYLER.

